In a recent EE Times 2013 Embedded Market study, Android was the OS of choice for future embedded projects among 16 percent of the survey's participants, second only to 'in-house/custom' (at 28 percent). But if a spectrum of disparate approaches can be lumped together as a single option, why not aggregate the various shades of Linux to see how they compare? "Parsing the EE Times data this way makes it abundantly clear that Linux truly dominates the embedded market."

"Avionics. If we missed a deadline, a computer crash would be the least of our worries"

I know your half joking, but my initial impression would be that realtime flight control systems are far less demanding (in terms of schedulers) than even a basic audio daemon doing realtime effects. The difference being that with an audio application, we can wave our hands and merely assume the upper bound exists for priority threads (and probably be right if distortions never happen under full load), but with important control systems someone needs to compute and actually prove a deterministic upper bound.

What is the sample/control rate used by avionic controllers?

What kind of systems would start failing on an aircraft if an operation happened 1ms late? Even the fastest servos are pretty slow in computer terms.

Do you use multi-process, multi-threaded code with multiple threads running on the same core such that the OS scheduler plays a significant role?

Feel free to educate me since I have no experience in the matter, but I am curious.